Flowmeter, flow detecting switch, control method of flowmeter, control method of flow detecting switch, and recording medium having recorded a control program

摘要

A frequency measuring apparatus and a flowmeter which can carry out highly accurate measurement in a short time is provided. A measured pulse signal from a frequency detecting portion is outputted to a first counter as a count input and to second counter as a control signal. The first counter counts the number of the input pulse in each period of the first timer output according to the output from the first timer having been set in 1 second period, for example. The second counter carries out the count of the reference clock from the rising point of the input pulse and measures the period of the input pulse. The arithmetic processing portion calculates the input pulse signal frequency up to the decimal portion on the basis of the count value of the first counter, the count value of the second counter at a generation timing of the output signal from the first timer, and the period of the input pulse.